FREE Exponential Growth & Decay Lesson | Algebra 1 Day 1 | ELL Scaffolded

★ FREE COMPLETE LESSON — Exponential Growth & Decay, Day 1 ★

Love this free lesson? Grab the full 5-day PBL unit with 4 real-world datasets → [link to paid product]

📋 WHAT YOU GET (8 pages, ready to print & teach)

This is Day 1 of a 5-day Project-Based Learning unit on exponential growth and decay. It's a complete, standalone 55-minute lesson — not a teaser or a sample of half a page. Print it tomorrow and teach.

Included in this free download:

✅ Cover page with UM Printables branding ✅ Teacher instructions + standards alignment (CCSS HSF-LE.A.1, A.3, B.5, BF.A.1a) ✅ Vocabulary card for "Exponential Growth" with formula + common-error tip ✅ Visual concept anchor (growth vs. decay curves, linear vs. exponential comparison) ✅ Complete Day 1 lesson: Launch: The legend of the chessboard (engaging hook with data table) Mini-lesson: Deriving A(t) = A₀ · bᵗ Worked example: Bacterial growth modeling Guided practice: 3 problems for partner work Exit ticket: 3 self-assessment questions ✅ Detailed answer key with step-by-step solutions (Given → Formula → Substitution → Interpretation) ✅ ELL scaffolds: sentence frames, structured discourse stems, vocabulary pre-teach ✅ Marketing page linking to the full 5-day unit 🎯 WHY THIS LESSON WORKS

The chessboard hook actually works. Students who zone out during "y = abˣ" lean in when they hear about the king who promised grains of wheat — only to discover he owes 18 quintillion grains by square 64. The pattern-finding launch naturally produces the word "doubles," which you name as exponential growth. Students derive the formula themselves.

Real differentiation, not just a label. The vocabulary card includes a "Common Error to Avoid" tip that pre-empts the #1 misconception (students writing b = 4 instead of b = 1.04 for "4% growth"). The sentence frames give multilingual learners an entry point without dumbing down the math.

Answer key shows the thinking, not just the answer. Every solution follows the same 4-step structure: Given → Formula → Substitution → Interpretation. Students learn how to communicate mathematically, not just compute.

📏 STANDARDS ADDRESSED

Standard

Description

HSF-LE.A.1Distinguish linear vs. exponential situationsHSF-LE.A.3Observe exponential eventually exceeds linearHSF-LE.B.5Interpret parameters in contextHSF-BF.A.1aWrite explicit function from context

👥 WHO THIS IS FOR

Algebra 1 teachers (grades 9–10) introducing exponential functions Math teachers with multilingual learners / ELLs at WIDA levels 1–4 Teachers trying project-based learning but unsure where to start Anyone who wants a high-quality, immediately-usable lesson — no prep required ⬆️ WANT THE FULL 5-DAY UNIT?

This free lesson is Day 1 of a complete PBL unit. The full resource includes:

Day

Topic

Real Dataset

Day 1Foundations (this free lesson)Chessboard hookDay 2Compound InterestReal Federal Reserve ratesDay 3U.S. PopulationCensus data 1790–2020Day 4Bacteria + Viral SpreadE. coli + SIR epidemic modelDay 5Student Choice BoardCulminating data-story project

The full unit also includes:

50+ pages of instructional content 8 labeled diagrams and visual concept anchors Detailed step-by-step solutions for every problem Two complete rubrics (project + participation) 30-term glossary with embedded formulas Extension activities + differentiation strategies → [Get the full 5-day PBL unit here]

Exponential Growth & Decay PBL | Real-World Algebra 1 Project | ELL Scaffolded

❓ FREQUENTLY ASKED QUESTIONS

Q: Is this really a complete lesson, or just a teaser? A: It's a complete 55-minute lesson. Launch hook, direct instruction, worked example, guided practice, exit ticket, and answer key. You can teach it tomorrow without needing anything else.

Q: What's the catch? Why is it free? A: No catch. This is Day 1 of a 5-day unit, and I'm confident that if you love Day 1, you'll want Days 2–5. The full unit covers compound interest (real Fed rates), U.S. census data, bacterial growth, and viral spread — all with the same level of detail.

Q: Do I need anything special to teach this? A: Just a scientific calculator per student and a way to project the vocabulary card and visual anchor. No graphing calculators, no software, no prep.

Q: Is this ELL-appropriate? A: Yes. The vocabulary card, sentence frames, and structured discourse stems are embedded into the lesson — not optional add-ons. The unit follows SIOP Model and WIDA ELD (2020) frameworks.

Q: Can I use this for a sub plan? A: Yes. The lesson is fully self-contained and scripted. A substitute with basic Algebra 1 knowledge can deliver it.

💬 HOW TO USE THIS FREE RESOURCE

Download (click the green button above) Print pages 3–7 for each student (cover and marketing page are for you) Project the vocabulary card (page 3) and visual anchor as students enter Teach the 55-minute lesson using the scripted launch, mini-lesson, and guided practice Love it? Click the link on the last page (or in this description) to get the full 5-day unit ⭐ LOVE THIS FREE LESSON?

Please leave a review! Reviews help other teachers find this resource and help me know what to build next. Click the "Leave a Review" button on your "My Purchases" page (free downloads count too!).